The conjecture that any developments that are much later discarded for a better approach are a waste of time doesn't really address how one can never know what

The conjecture that any developments that are much later discarded for a better approach are a waste of time doesn't really address how one can never know what ultimately will prove most useful for future innovations in the first place. Or that, you know, some people like building stuff just for the pure enjoyment of building. Which IMO is just as important.